Ca[sub 2]Al[sub 2]SiO[sub 7]:Ce[sup 3+], Tb[sup 3+]: A White-Light Phosphor Suitable for White-Light-Emitting Diodes

Rare-earth-activated, white-emitting phosphors , were prepared under a weak reducing atmosphere by conventional solid-state reaction and their luminescence properties under excitation were investigated in detail. shows excitation at short-UV wavelength light . , showed optimal excitation at long-UV light excitation . By incorporation of , an efficient energy transfer from to was found and generated white light under long-UV excitation. The emission spectra consisted of a blue band and a green band , the relative intensities of which changed with the rare earth dopant concentration and . As a result, the optimal concentration for the best luminescence intensity was obtained in , 0.030 , and the closest to daylight white emission was found with a composition of , 0.020 , which has chromaticity coordinates , . This is considered to be a potential white-emitting phosphor for white light-emitting diodes.